iwinfo: add page (#15848)

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

pages/linux/iwinfo.md

@@ -0,0 +1,28 @@
+# iwinfo
+
+> Retrieve information about wireless interfaces on OpenWrt.
+> More information: <https://openwrt.org/docs/guide-developer/ubus/iwinfo>.
+
+- List all available wireless interfaces:
+
+`iwinfo`
+
+- Display detailed information on a specific wireless interface:
+
+`iwinfo {{interface}} info`
+
+- Scan for nearby wireless networks visible to the interface:
+
+`iwinfo {{interface}} scan`
+
+- List connected devices:
+
+`iwinfo {{interface}} assoclist`
+
+- List channels supported by the interface:
+
+`iwinfo {{interface}} freqlist`
+
+- List available transmit power levels for the interface:
+
+`iwinfo {{interface}} txpowerlist`